Abstract Detail

Mycological Section

Grome, Kimberly [1], Beckstead, Julie [2], Van Volkom, Kaitlin [2], Shuster, Abbey [2].

Residual effects of imazapic on the invasive cheatgrass and native grasses in a restoration setting.

Cheatgrass (Bromus tectorum) is an invasive grass species that has taken over natural areas in the Intermountain West and has resulted in the displacement of native species. Imazapic is a pre-emergent herbicide and it is frequently used in ecological restorations to remove B. tectorum. Therefore, we predict that native grasses will escape damage, whereas B. tectorum will be negatively impacted.  We investigate the residual effects (14 months post application) of imazapic within a restoration setting and focused our studies on B. tectorum and the native grass squirreltail (E. elymoides). These residual effects were quantified by planting B. tectorum and E. elymoides seeds into field-collected seed-zone samples from impazapic treated plots and control plots at Hanford Reach National Monument in central Washington.  The seed-zone samples were placed on top of pots to allow for extended root growth and allowed to grow for 6 weeks. Our results showed that emergence did not differ between the control and imazapic treatments for either species; emergence exceeded 91%.  However, there was a significant difference in emergence between the species. Bromus tectorum had a higher emergence of 98% compared to only 91% emergence of E. elymoides. Although the emergence of both species was high, the seedlings were negatively impacted by the imazapic treatment and this effect differed between species. Bromus tectorum experienced 71% more dead seedling tissue compared with the non-treated controls. Whereas the E. elymoides experienced 51% more dead seedling tissues compared with the non-treated controls. Although B. tectorum was impacted more negatively, we did not expect this high of a negative impact on the native grass E. elymoides, especially 14 months after the application. These results indicate that imazapic has a lasting residual effect on young seedling growth but not emergence. This being said, caution should be used when using imazapic in a restoration setting where native grass seeds are added even one-year post application.  

1 - Gonzaga University, Biology, 502 E Boone Ave , MSC#2358, Spokane, WA, 99258, USA
2 - Gonzaga University, Biology, 502 E Boone Ave, Spokane, WA, 99258, USA

Keywords:
Restoration Ecology
Herbicide Treatments
seedling establishment
Bromus tectorum.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PMY002
Abstract ID:278
Candidate for Awards:None